VMM/GIM: Add hypercall support and KVM spinlock support.

VMM/GIM: Implemented KVM paravirt. provider.

VMM/GIM: empty prototype.

VMM/GIM: Get rid of separate fEnabled field, just use the provider to figure out whether it's enabled or not.

VMM/GIM: nits.

GIM nits: Must check version and config when loading saved state. Saved state version macros shouldn't be called guest-interface-manager-saved-state-manager-version, but rather guest-interface-manager-saved-state-version. SSM failures are sticky, so no need for AssertRCReturn for every SSM call, only when we want to use the data. First sentence of function documentation provide a brief description of the function and for readability purposes stand alone (also, keep it short when possible).

VMM/GIM: Keep Minimal GIM provider guest agnostic.

VMM/GIM: Make guest-OS Id as part of the saved states as it could be useful in the future to have it in there.

Comments and nits.

VMM/GIM/Minimal: OS X bits.

VMM/GIM: More bits for Hyper-V implementation.

VMM/GIM: Mapping of GIM MMIO2 regions and Hyper-V provider work.

VMM/GIM: Hyper-V provider, work-in-progress.

VMM/GIM: Introduce the Minimal provider.

GIM: Skeleton, work in progress.